1. Field of the Invention
This invention relates to a mechanism for operating the dump doors on a railway hopper car. More particularly, this invention relates to a mechanism for opening and closing a plurality of dump door pairs covering a plurality of longitudinally spaced hopper outlet openings on the lower end of a railway hopper car.
2. Description of the Prior Art
As shown in U.S. Pat. Nos. 3,596,609 and 4,508,037, one mechanism used in the prior art to open and close a plurality of longitudinally spaced hopper dump door pairs includes a longitudinally extending operating rod which is moved longitudinally by a pressurized air cylinder or other means. This longitudinally extending rod is connected with a plurality of door operating levers connected to actuating shafts extending transversely below the hopper car body. The actuating shafts are rotatable and are connected to linkage mechanisms which may be rotated to open and close the dump doors. Longitudinal movement of the operating rod rotates each door operating lever. Each door operating lever rotates an actuating shaft, which in turn actuates a linkage mechanism to open and close the doors.
One disadvantage of this type of arrangement is that the door operating lever transmits the rotation to the door operating linkage through an actuating shaft. The actuating shaft is flexible and less structurally efficient due to its relatively small diameter on the axis of rotation. The linkage mechanisms are spaced laterally from the levers, resulting in undesirable torques within the mechanism, and also requiring more area on the underside of the hopper car, reducing the size of the dump doors. Also, the shaft extends below the car body and is vulnerable to damage from impacts.